There are many different incontinence disposable child and adult care products on the market including diapers, training under pants, and temporary swimsuits. Many of these products are constructed with nonwoven substrates including but not limited to nonwoven polyethylene or nonwoven polypropylene films. There is a desire within the marketplace to print graphics on these nonwoven substrates for appearance such as mere decoration or for utility such as indication of wetness. These substrates are typically printed with flexographic or rotogravure presses for these products, however, the printed inks have low color transfer resistance so as to discolor anything the nonwoven substrate may come into contact with such as clothing, carpet and furniture. The nonwoven substrate is not porous such as paper and thus the printed ink easily transfers from the substrate onto contact substrates/objects. Thus, there is a desire for the printed graphics on nonwoven substrates to have augmented color transfer resistance properties.
U.S. Pat. No. 5,458,690 describes printing block urethane inks on nonwoven substrates for improved colorfastness and color transfer resistance. The block urethane ink system specifically mentioned is Parabond from Sun Chemical which is composed of a block urethane resin, vinyl resin, wax and epoxidized soybean oil along with pigments. U.S. Pat. No. 5,695,855 discloses adhesive inks for improved nonwoven products. U.S. Pat. No. 5,853,859 describes combining a latex polymer with pigment and a cure promoter for colorfastness when exposed to a wide range of pH liquids. International Publication Number WO 021051644 A1 discloses a two part cross linked ink with a two part cross linked coating.
However, none of the existing inks provide for use of conventional flexographic or rotogravure printing inks on nonwoven substrates having the same properties of enhanced color transfer resistance as on other substrates. Accordingly, a need exists for an ink which can be used in both flexographic or rotogravure printing on nonwoven substrates while exhibiting and maintaining enhanced color transfer resistance properties.